CULTIVATION IN DRY AREAS 163 



less followed by the harrow or the grain drill. (4) On 

 land that is much strewn with stones, but where only 

 a few are present it may serve as a means of conveying 

 them to the borders of the field. 



Seed drills and their uses. Seed drills are of sev- 

 eral kinds. They include the single disc drill, the double 

 disc drill, the double disc press drill, the hoe drill, the 

 shoe drill and several makes of broadcast seeders. For 

 ordinary sowing in dry areas, the hoe drill and the shoe 

 drill are but little used. It is very largely confined to 

 the three types of disc drill first named. There is also a 

 place of no little importance for the small disc drill, 

 which more commonly has but five discs. There is al- 

 most no place for broadcast seeders on the dry farm, as 

 they do not bury the seed to a uniform and in many in- 

 stances to a sufficient depth. Each of the four kinds of 

 disc drills named will fill a place better than can be 

 filled by any of the others. 



The single disc drill (see p. 164) opens a furrow 

 in the soil for the seed which drops into it, and it 

 is covered by the earth falling back upon it behind the 

 disc. The double disc drill (see p. 165) makes an 

 opening into the soil between each two discs. The seed 

 falls into this opening, where it is deposited at a uniform 

 depth. The disc press drill (see p. 177) has a wheel 

 following each drill mark, which firms the earth around 

 and over the seed. The small disc drill is for use 

 where only one horse can work, as between corn rows. 



The single disc drill has adaptation for sowing grain 

 on land that may be too rough or too moist to use the 

 double disc drill on it to advantage. On rough and espe- 

 cially on stony ground, it will open a seed furrow more 

 readily, and it will clog less readily in overmoist ground. 

 The double disc drill has highest adaptation for clean 

 land. As it drops the seed at the bottom of the furrow, 

 it is first covered by moist earth, which, under dry condi- 



